1. Field of the Invention
The present invention relates to a washing machine, more particularly, to a control method a spinning cycle in a washing machine which can minimize over-vibration generated in a spinning cycle and can enhance drainage and dehydration capability.
2. Discussion of the Related Art
In general, a washing machine is an electric appliance used most commonly in a house. The washing machine washes cloth items, clothes and beddings (hereinafter, the laundry) by using friction poser of wash water current generated by rotation movement and shock power with the laundry, in a state where wash water, detergent and the laundry are mixedly loaded into a drum.
The washing machine is classified into a pulstor type washing machine having a drum vertically installed therein and a drum type washing machine having a drum horizontally installed therein, and performs washing by means of a washing algorithm including a washing, rinsing and spinning cycle.
Commonly, in a washing cycle, detergent, wash water and the laundry are loaded in the washing machine and dirt of the laundry is removed by chemical action of detergent and physical action of a drum.
In a rinsing cycle, wash water not mixed with detergent is supplied and detergent and dirt remaining on the laundry may be rinsed.
Finally, in a spinning cycle, a drum is spinned at a high speed to dehydrate the laundry after a rinsing cycle is completed.
As describing a spinning cycle more specifically, first of all, water is drained and a laundry-balancing is performed where a motor repeatedly rotates a drum in a clockwise/counter-clockwise direction to prevent the laundry from being entangled.
After the laundry-balancing, a dehydrating, in other words, a high speed spinning is performed by increasing RPM of the motor in a predetermined direction to remove moisture contained in the laundry.
If the laundry is not uniformly distributed during the spinning cycle, there might be unbalance of the laundry. Thus, it is needed to sense the RPM of the motor in a beginning of a spinning cycle, such that vibration or unbalance of a body may be sensed by variation of RPM.
Here, once the laundry unbalance is determined more than an allowable range, the drum is stopped and re-rotated. Once the laundry unbalance is determined less than an allowable range, the RPM of motor is increased gradually.
That is, in case the drum is rotated in more than the allowable range of laundry unbalance in the beginning of the spinning cycle, there may be bad influence on entire rigidity of the system. Thus, it is preferred to start the high speed spinning after limiting the laundry unbalance less than the allowable range.
However, a spinning cycle according to the related art senses laundry unbalance only once when accelerating the motor before starting a high speed spinning, thereby resulting in mal-sensing of laundry unbalance.
Especially, in case that laundry unbalance is mal-sensed in a spinning cycle at 200˜300 RPM in that resonance is generated, severe vibration is generated enough to cause damage such as glass scratch of a door or washing machine moving.
Also, since water leaked from the laundry by centrifugal force may be stuck to a wall of the drum after a predetermined RPM of high speed spinning according to the related art, normal drainage may not be performed.
Thus, the remaining water within the drum may be a cause of severe vibration or noise in a high speed spinning, thereby resulting in customer dissatisfaction.